Wavelet Analysis of Doppler Flow Velocity Waveforms from the Ocular Circulation Detects Abnormalities in Micro-vascular Function in Heart Failure

Aims: Many pathological processes may result in Heart Failure (HF), however, the final clinical phenotype appears to be common to all aetiologies. Microvascular abnormalities in HF have been demonstrated in a variety of vascular beds however the effect of HF on the retrobulbar circulation is not known. We employed a novel method of analysing blood flow velocity waveforms in order to quantify changes in the Doppler signal obtained from the retrobulbar arteries between HF patients and controls. FMD was also assessed. Methods and Results: 32 patients with systolic HF on maximal medical therapy and 10 age and sex-matched controls were studied. Doppler waveforms were obtained from the ophthalmic, central retinal and brachial artery in all subjects. Waveforms were analysed using a wavelet technique which expressed each waveform in constituent frequency bands, allowing direct comparisons to be made. Significant differences were found in ophthalmic and central retinal waveforms but not brachial waveforms between patients and controls. Flow mediated dilatation was also found to be abnormal in patients. Conclusion: This study suggests that abnormalities in microvascular function in the retrobulbar circulation are present in HF and that these changes can be detected by a novel wavelet analysis technique.